Aristotle believed that the earth was the center of our universe. in the late 1400's, copernicus spoke against this popular belief and stated that the sun is the center of our universe. today, we now know that copernicus was correct. should all the work of aristotle now be thrown out? a) yes. aristotle was not a true scientist. b) no. it has not yet been proven that aristotle was wrong. c) no. science is always changing based on new ideas and data. d) yes. since aristotle was wrong once, he was probably wrong on everything.

Achemical reaction (also known as a chemical change) produces substances that are chemically different from the starting materials. an example of a chemical reaction is the formation of water from hydrogen and oxygen gas.in a physical change, a substance changes its physical appearance but not its chemical identity. an example of physical change is the formation of liquid water from solid water, a familiar process called melting. physically, liquid water looks very different from solid water (ice) but the chemical identity, water, is the same for both. which of following changes that affect the composition of our atmosphere involve physical changes and which involve chemical reactions? oxygen gas changes to ozone during thunderstorms carbon dioxide is produced by the combustion of gasoline in an automobile engine. when coal, oil, and natural gas are decomposed in landsills they produce methane gas. freezing rain develops when a warm air mass overrides a cold air mass. fog forms from water vapor when the temperature drops below the dew point

What are the primary responsibilities of a chemical engineer involved in "r& d"? develop large scale manufacturing operations discover new products and processes training of new chemists determine products needed by consumers

Which of the following would be an accurate picture of the earth during the summer time of the northern hemisphere?